A mobile communication service provider acquires a frequency band to provide a service and then divides the acquired frequency band to partial frequency bands (Frequency Assignment, FA).
In addition, a service area is configured as an OMNI cell or a sector-divided one according to the type of the service area and the number of subscribers.
The partial FAs are allocated to sectors. Usually, fixed multiple FAs are allocated to cover up a maximum call rate in each sector.
For example, if one sector requires up to 3 FAs, a total of 9 FAs are required in a base station and some components, units, and equipments are needed to process the 9 FAs.
By the way, the probability of an occurrence of maximum calls in each of the 3 sectors simultaneously is very low. Therefore, a service provider normally assigns 2 FAs to each sector and then may assign one FA, coming from a near sector with a low call rate, to a sector requiring 3 FAs. If they can assign FAs dynamically, a base station is able to run with a small number of FAs (6 FAs) totally, not initially having with 9 FAs.
If 9FAs and related equipments are already installed, the operation efficiency of the base station will be improved by increasing the maximum number of allocable FAs from 3 FAs to 4 FAs in a sector.
However, because a fixed N:1 combiner or a fixed 1:N divider, and several switches are used in an existing technology, this connection structure is complicated. As a consequence, a big insertion loss and cost are drawbacks, if ever implemented.